Conventional cameras are typically provided with a camera body having a taking lens which is fitted to the camera body, a viewfinder for determining the field of view of a photographic scene and an electronic flash unit integral to the camera body or else directly attached thereto which provides adequate illumination to allow a subject to be photographed. Typically, inexpensive cameras are provided with picture taking lenses having a fixed focal length whereby correctly exposed, that is relatively blur-free photographs, can be taken from a range of distances of between approximately five feet to infinity. This range is considered adequate for a statistically high percentage of photographs.
However, these inexpensive cameras, such as conventional 35 mm NSLR cameras manufactured by the Eastman Kodak Company, among others, do not produce properly exposed pictures when close-up pictures are taken (that is, where the subject to camera distances are less than five feet). The resulting prints can on occasion be out of focus due to the capability of the optics used. In addition, the quality of close-up photographs can also be effected by the electronic flash unit conventionally used by these cameras which provide adequate illumination at distances in the range of about 5 to 14 feet ( 1.5 to 4.3 meters), but produce excessive amounts of flash output when photographs are obtained at closer distances.
To allow close-up pictures to be taken lens elements having a shorter focal length could be added to the camera, but this reduces the ability of the camera to take properly focused pictures for subjects at distances greater than 10 feet ( 3 meters). In addition, the flash unit may still produce excessive illumination for close-up photography.
U.S. Pat. No. 3,836,927 describes a camera attachment having a mounted assembly, including a close-up diopter lens, which mounts to the front of a camera taking lens to allow close-up photographs to be taken. The assembly also includes a sliding member which can reduce the size of the flash aperture to thereby decrease illumination on a subject. The described attachment, however, must be separately removed in order for the camera to be reverted into a "normal" (not close-up) picture taking mode. This requires additional steps for the photographer which are not always convenient, requiring independent movements or removal of each component of the mounted assembly to alter the mode of the camera to allow for either close-up or normal picture taking. In addition, this assembly is not suited to other picture taking modes, such as tele-photo, or those using wide angle lenses and the like.
There is a need to provide a camera attachment which can be conveniently attached to the camera whereby the camera can be placed into separate picture taking modes without having to remove the attachment or otherwise interfere with the taking of photographs.